Contributed to the apache/spark repository by developing a new Spark SQL function, make_time, which constructs time data type objects from hour, minute, and second inputs. This feature included robust error handling and comprehensive unit tests to ensure reliability and correctness. Additionally, addressed a reliability issue by fixing a hang that occurred when the MDC was unavailable in Spark executors, and improved MDC-related logging to enhance observability and error diagnosis. The work demonstrated strong backend development skills, leveraging Scala, SQL, and Apache Spark to deliver targeted improvements in both feature capability and system stability within a complex data processing environment.